Nectriacanker on a European beech (Fagus sylvatica) trunk. Overview. Worldwide, Nectria fungi cause several common canker and dieback diseases, especially in hardwood trees. What causes nectriacanker disease is one of the several nectria fungal species. These fungi are opportunistic and attack trees at their weak spots from injury, pruning, root damage, freezing, pest infestations, and other diseases. Almost all trees are susceptible to cankers, a disease of the bark or wood of a tree, caused by the Nectria fungus. It is most common in regions with a cool, humid climate. Most hardwoods with such injuries are susceptible to attack by Nectria. Slightly sunken areas (cankers) develop around wounded or damaged tissue. Smooth-barked areas are generally darker brown than the surrounding bark. If the bark of the tree is rough and dark, the canker is... Nectriacanker is a common fungal disease in eastern hardwood forests and occurs on a variety of host species. It is also an important disease in apple orchards and occurs on susceptible ornamental tree species. Nectriacanker is a common and potentially lethal disease that affects many species of trees and shrubs. This disease can cause significant damage on newly planted, as well as established, trees and shrubs that are under stress. Nectriacanker on a honey locust tree. A fungal canker disease affecting numerous hardwood species, characterized by distinctive target-type cankers with raised, calloused edges and salmon-red pustules. The disease is perennial and can eventually girdle branches or stems, particularly problematic on recent transplants. Target cankers are common and usually easily recognizable diseases on the stems of hardwood trees. Learn about a few examples.Nectriacanker caused by Neonectria ditissima on Acer saccharum (sugar maple). A perfect example of a target canker. DISEASE CYCLE Nectria spp. survives in canker tissue where fruiting bodies are produced. Spores emerge from the fruiting bodies and infect through wounds or weakened plant tissue.B Tree severely infected by nectriacanker. C Close-up of coral-colored fruiting bodies. Cause Neonectria ditissima (formerly Nectria galligena), a fungus, occasionally causes a perennial target-shaped canker on the trunk and limbs of Oregon white oak. In response to infection, the tree forms a callus ridge around the initial canker. • Nectria fungi are generally saprophytic, decaying al-ready-dead wood, but can become weakly parasitic if infecting weakened, stressed trees.Do not prune honeylocust in wet conditions, and avoid pruning other susceptible trees in wet weather if active cankers are observed. Black spot Nectriacankers, caused by Nectria nigrescens, appear very similar to Thyronectria cankers, and are best distinguished from P. austroamericana by cultural characteristics, morphology of the asexual fruiting structures, and ascospore morphology. HOST PLANTS: Nectriacanker is one of the most common diseases of hardwoods in North America. It affects more than 60 species of trees and shrubs. Nectriacanker is a concern for newly established and stressed trees and shrubs, as the cankers grow when the host is stressed. The main symptom of this disease is the production of dark and wet areas on branches and twigs.
